A cut and raked crop that has been dried or otherwise prepared in a field, such as hay, straw or other agricultural material is often gathered, compressed and shaped by an agricultural baler. There are several types of balers that are commonly used, each resulting in different types of bales. Some are rectangular and some are cylindrical of various sizes. Bales can be bound with netting, strapping, wire or traditionally twine. A baler that produces small rectangular bales, often called square bales, often produce bales that are typically wrapped with two strands of knotted twine. The bales are light enough for easy handling and typically weigh from 40 to 80 pounds. A bale is formed by a series of processes performed by the square baler including lifting the windrowed material, hereinafter referred to as hay, by way of the pickup portion of the baler. The hay is then moved by way of an auger into a chamber that has a feeding fork. The feeding fork moves the hay in front of a sliding plunger with a cutting edge that cuts the hay and moves the hay in the chamber into previously packed hay therein causing the hay to be compressed. Once a predetermined amount of hay has been gathered in the chamber, as measured by the amount being extruded through the opening at the rear of the chamber, a mechanism is triggered causing the twine to be threaded through the hay, cut and then knotted thereby forming the bale and one portion of the twine is retained to start to receive hay for the next bale. As the bales are moved through the compression channel out to the rear of the baler, the baled hay is then either loaded onto a wagon or dropped into the field for later retrieval.
The plunger mechanism of the square baler requires a considerable amount of energy to cut and compress the hay. Typically the mass of the plunger is augmented by a flywheel connected so that energy from the tractor during the non-compressing part of the stroke is stored in the flywheel and then is expended as the plunger compresses the hay. Some older balers including some currently being used by the Amish have a gasoline engine mounted thereon with a belt drive directly driving the flywheel of the baler. Typically balers have the flywheel oriented towards the front of the baler with the PTO shaft from the tractor directly driving the flywheel that is then interconnected to the plunger.
Another type of baler in common use today is one that produces large rectangular bales. These larger rectangular bales are many times larger than the smaller bales previously discussed. The baling concept is similar in that the hay is picked up and then compressed in a chamber and extruded from the back of the baler once the desired size is reached and the twine is secured around the bale. The large rectangular balers require even more energy and a larger flywheel to provide the sustained energy requirement during the compression portion of the plunger stroke.
The problem with the larger energy requirement of larger balers is that a large flywheel is required to even out the power demands of the baler. Another problem with the prior art is that in light crop conditions or uneven terrain where forward travel speed is limited causes the prior art balers to compact a portion of the bale several times before gathering enough material to introduce to the compression chamber for compacting by the plunger. This causes a portion of the hay in the bale to be recompacted causing undue damage to the hay as it is mechanically impacted, compressed and relaxed with each stroke.
What is needed in the art is a baler that alters the plunger drive speed and reduces the need for a large flywheel.